Fastening means for a rotational fastener and method

ABSTRACT

The rotational fastener such as a nut element has an aperture with helical ribs on the circumferential walls spaced by breaks in the periphery of the aperture. These helical ribs commence at the breaks near one surface of the element and extend axially and circumferentially, the ribs increasing in radial height with increasing distance from the one surface. The ends of the ribs serve as teeth for engagement with a shank and cut grooves in the shank.

United States Patent 11 1 Tinnerman Dec. 4, 1973 FASTENING MEANS FOR AROTATIONAL FASTENER AND METHOD [76] Inventor: George A. Tinnerman, 3600Stewart Ave., Lakewood, Ohio 33133 22 Filed: Sept. 24, 1971 21 Appl.No.: 183,662

Related US. Application Data [60] Continuation of Ser. No. 6,153, Jan.27, 1970, abandoned, which is a division of Ser. No. 640,213, March 22,1967, Pat. No. 3,491,646.

52 Us. 01. 10/86 F 51 Int. Cl B2ld 53/20, B21d 53 24 58 Field 61 Search10/86 R, 86 F; 85/32, 32 v; 72/377, 379

[56] References Cited UNITED STATES PATENTS 561,913 6/1896 Paquette85/32 v 2,723,584 11/1955 Parker 85/32 v 2,832,972 5/1958 Richards 10/86F 2,896,495 Crawford 85/32 V 3,206,967 9/1965 Holton 10/86 R 3,345,89910/1967 Fiddler... 85/32 V 3,368,444 2/ 1968 Holton 10/86 R 3,387,4816/1968 Harvey 72/377 3,160,189 12/1964 Hughes 85/32 R 2,002,671 5/1935McLaughlin 10/86 F Primary ExaminerCharles W. Lanham AssistantExaminer-E. M. Combs Att0rneyRevere B. Gurley 57 ABSTRACT The rotationalfastener such as a nut element has an aperture with helical ribs on thecircumferential walls spaced by breaks in the periphery of the aperture.These helical ribs commence at the breaks near one surface of theelement and extend axially and circumferentially, the ribs increasing inradial height with increasing distance from the one surface. The ends ofthe ribs serve as teeth for engagement with a shank and cut grooves inthe shank.

5 Claims, 10 Drawing Figures PMENTHIHH. 41m

GEORGE A. TINNERMAN PATENTEDDEC m 3775790 SHEET 2 BF 2 FIG. 8'

INVENTOR GEORGE A. TINNERMAN cal end surfaces 1 FASTENING MEANS FOR AROTATIONAL FASTENER AND METHOD This is a continuation of applicationSer. No. 6,153, filed Jan. 27, 1970, now abandoned, which is a divisionof application Ser. No. 640,213, filed Mar. 22, 1967, now US. Pat. No.3,491,646.

These ribs are formed by swaging the edges of the aperture between thebreaks axially and radially inwardly,

using a punch element having helical surfaces to swagc the ribs. Twoopposed punches may be used from opposite sides of a sheet or plateelement, and two sets of ribs are formed from the two sides. Preferablythe ribs of two sets lie in the same helical paths.

A- thickened boss may be formed for the fastening means if a sheetmaterial is too thick. Two punch ele: ments having circumferentialshearing edges and tapered sides internally of the edges are opposed toeach other and engage opposite sides of a sheet elementto shear thematerial about the periphery of the punch element which then compressesthe material radiallyto expand it axially. The aperture may be made inthis boss and ribs formed therein as described above.-.

The fastener element and shank may' be secured more firmly againstloosening or reverse rotation by an axial impact on the shank to set theteeth of the ribs into the shank, thus increasing the resistance toreverse rotation.

SUMMARY OF INVENTION This invention relates to fastening means on anapertured article to engage a shank by relative rotation, and a methodof forming such fastening means. The article, illustrated as a sheet orplate, has an aperture which is formed with cylindrical wall portionsspaced by breaks or notches. The edges of said cylindrical wall portionsadjacent one surface between the notches are swaged radially and axiallyto form helical ribs or partial threads I on the wall portions betweenthe notches. These ribs are formed by a punch element havingheliengaging the edges between the notches. v I

Two sets of partial threads orribs may be formed by swaging on bothsides of the plate or nut element, and the ribs of each set may liein-the same helical paths as the ribs of the other set. An articlehaving a set or plurality of sets of such partial threads or ribs,- whenrotated on a smooth shank or stud, may cut grooves in the stud, the lowend of the rib at the adjoining break forming a tooth for cutting'thegroove. If a second set of ribs is formed on the same article fromthe-opposite side, the second set when in the same helical paths cutsthe same groovesdeeper, as the higher ends of the ribs act as thecutting teeth.

A thin sheet element may be thickened sufficiently for forming partialthreads by thickening at one point. A pair of opposed punch elementshaving peripheral cutting edges partially shear through the material,and compact the surrounded material radially to increase its thickness.

This application is a division of my application Ser. No. 640,213, filedMar. 22, I967. DRAWINGS FIG. 1 is a plan'view of an apertured fastenerelement to be formed with the fastening means of this invention.

FIG. 2 is a plan view of the element of FIG. 1 with the fastening meansformed therein.

FIG. 3 is a cross section on line 33 of FIG. -2, showing'fthe punchelement used to form the fastening means. g

FIG. 4 is a cross section on line 4-4 of FIG. 2.

FIG. 5 is a cross section of a modification, on ,line' 5-5ofFIG. 7.

FIG. 6 is another cross section on line 6-6 of FIG. 7, showing the punchelements used to form the fastening elements. y I FIG. 7 is a plan viewof the modification of FIG. 5.

FIG. 8is a partial cross section of a fixed fastener element applied toarotating shank to secure panels or brackets to each other. I

FIG. 9 isa plan view ofa' formation of a sheet member to be used as afastener element.

FIG. 10 is a cross section on line l0- l0.of FIG. 9', showing the punchelements used in the formation of the fastener element.

DESCRIPTION OF THE INVENTION faces 12 of the nutelement 10 by'a punchmember 14 Q as shown in FIG. 3. The end of this punchmember l4 has acontinuous wall with an outer diameter slightly own groove, so that theshank is formed with spaced surfaces 14a of the punch member swage ordeform the comers or spaced edge portions ofarcuate surfaces l2 intohelical formations corresponding to partial threads In the specific formshown to illustrate the principles of the invention, the punch memberwith identical helical surfaces forms identical threads or ribs 15, 16on the same level orequal-distances from the surface of article 10.These partial threads, therefore, lie in spaced helical paths andcorrespond to spaced threads.

After the nut element is formed by the punchmember 14, as shown in FIGS.2, 3 and 4, it. may behardened, if desired, as by carburizing, and theends of the partial threadswill form cutting teeth for grooving a shankon whichthe article such as a nut element is r0.- tated. The leading end17 of each partial thread or rib engages the shank to cut a groove inthe shank, the partial thread following in and deepening the groove. Asthe partial threads lie in spaced helical paths, the end of each partialthread acts as a cutting tooth to cut its helical grooves cut by the nutelement.

It is also possible to form two sets of ribs or partial threads fromopposite sides of a nut element 20 by opposed punch members 24 operatingsimultaneously, as shown in FIGS. 5 to 8. This formation not onlyprovides greatly increased strength by providing the double sets ofcutting threads, but may increase the strength even more due toincreasing the depth of the grooves.

The nut element with the arcuate surfaces 22 is held between the opposedpunch members 24 which are driven into the opening and engage thearcuate surfaces 22 between notches 23. Each punch member forms a set ofribs or partial threads 25, 26 and 28, 29, respectively, equally distantfrom the opposite surfaces of nut element 20, so that the nut elementwill be the same when viewed from either side.

In FIG. 8, the stud 30 having a smooth shank is rotated to threadthrough the fastener element 20, the teeth and ribs forming twoparallel, helical grooves 31 and 32 in the smooth shank. This fastenerelement 20 is staked tothe panel 34, and the flanged head of the stud 30clamps a second member 35 against the fastener element to secure members34 and 35 together.

It is important to note that the two sets of ribs as viewed from oneside are reversed, or are mirror im-' ages, so that the low ends 27a ofthe ribs 25, 26 on the entering side of the shank will cut initially asthe shank enters the opening. When the shank then engages ribs 28, 29,the high ends 27b of the ribs engage the stud to set as cutting teeth.If the ribs of the two sets are formed in the same two spaced helicalpaths, it will be seen that the high ends 27b of the correspondingfollowing ribs will continue in the grooves 31 and 32 formed in a shank30' by the entering teeth 27a, as shown in FIG. 8. Thus partial threadsor ribs and 29 may lie in the same helical path, so that the rib orthread 29 will follow in the groove 31 of the shank initially cut by ribor thread 25 and the low end 27a. When the shank reaches thread 29 inits axial movement, the high end 27b of thread 29 will engage in thegroove, so that this cutting tooth will deepen the same groove. Theresult is that two spiral grooves are cut to a greater depth byoperation of the second set of partial cutting threads. a

A further feature of the operation of this fastening means on an articleis that the low ends 27a of the ribs initially engaging the shank cutthe groove at first, but the high ends 27b of these ribs engage in thegroove on reverse rotation of the nut element. The high ends of the ribswill exert great pressure on the shank and will act as teeth againstrotation on the stud in the opposite direction. As a result, the nutelement will not become loose'on the stud and is unlikely to beunscrewed by external forces or vibration.

The reverse torque may also be increased between a shank member andnutelement by sharp blows on the shank to set the teeth of the ribs intothe sides of the grooves in the stud. It is possible in this manner toincrease substantially the resistance of the nut element to reverserotation off the shank, and this resistance may continue for severalturns of the nut element.

In many cases, the sheet material may not be of sufficient thickness forthis formation, and applicant in FIGS. 9 and 10 shows a method ofthickening the material at a location where an opening is to be formedfor the partial threads. The sheet member 41 is placed between two punchmembers 42, each of which has a cupshaped end with a flat bottom surface44 and a conical peripheral surface 45 adjacent the periphery, theperipheral edge 46 being sharp to constitute a cutting edge. As the twopunch members approach each other, the cutting edges cut into thematerial on opposite sides and the conical surfaces compress thematerial radially between the punch members, thereby increasing thethickness at 47 between the punch members. The 'flattened bottomsurfaces 44 may limit movement of the punch members and form theflattened surface on the boss portion 47 of the member 41.

This rotating fastener or nut elementmay be encapsulated in a rigidsynthetic resinous plastic body, either in a molded body as shown inSer. No. 549,880, filed May 13, 1966, or in an assembled structure as inSer. No. 612,447, filed Jan. 27, 1967. The smooth shank preferably has atight fit with the plastic body, so that the nut element in compressingthe plastic will increase the frictional engagement with the shank. Whenused with a plastic base having substantial resilience, as a cup-shapedhollow base, the teeth on the nut or fastener element may beset in thegrooves of the shank by sharp impact on the shank as described above,the resilient base allowing sufficient movement for this purpose.Preferably, this action takes place while the torque force is stillapplied to the nut, the impact with the torque force appliedsimultaneously interengaging the teeth on the fastener element andgroove walls on the shank at the limit of rotational movement. The nutlocking eflect is substantial, and when combined with the resilientpressure exerted by thebase, eliminates any possibility of loosening ofthe fastener.

I claim:

1. The method of forming fastening means on an arti- I punch coaxial ofsaid aperture having a continuous wall of greater diameter than saidaperture and a helical surface on its end intersecting said wall on ahelical line to form a cutting edge, said punch having a cutting edgeextending completely about the periphery of the end, of j said punch andshaving the wall of said opening along a surface concentric to said walland on a helical lineintersecting the wall of said break to form ahelical rib along the wall of said aperture with one end of said ribintersecting the radially extending surface of said break and forming aninwardly extending tooth at the intersection, the radial height of saidrib increasing from said tooth and at any point being proportional tothe distance of the rib from the end of the aperture.

2. The method of forming fastening means as claimed in claim 1 in whicha plurality of breaks is formed in the wall of said aperture and eachrib extends from one break to the next succeeding break, and said punchhas a plurality of helical surfaces intersecting said continuous wall inhelical cutting edges to form a plurality of ribs on said wall of saidaperture, said ribs being spaced equal distances from the end of saidaperture, the end of each rib farthest from the adjacent surface at itsintersection with the break forming an inwardly height said article withconcentric arcuate'walls spaced by breaks in the periphery of theaperture, moving opposed punch members into said aperture toward eachother from opposite sides of said article, each punch member having acontinuous wail and helical surfaces on the end intersecting saidcontinuous wall in helical cutting edges of greater external diameterthan and concentric with the concentric arcuate walls of said aperture,swaging the edges of said arcuate walls by engagement of the helicaledges of each of said punch members with the edges of said arcuate wallsand with the helical edges on said punch members concentric to saidwalls to form helical n'bson said arcuate walls, each rib extendingalong one wall from a break adjacent the surface of said articleradially inwardly and axially toward the next break, the end of each ribnearest one surface at the intersection with the adjacent break formingan inwardly protecting tooth to engage a shank initially when insertedfrom the side with said one surface, the helical ribs formed by eachpunch member being spaced equal distances from the end of said apertureto form ribs equal in height, the helical ribs formed by opposite punchmembers lying in the same helical curves, so that the high end of onerib engages in the groove cut in the shank by the low end of theopposite rib.

4. The method of forming a female threaded fastener in thin, flat sheetmaterial which comprises exerting pressure on said material at an acuteangle to the surface about the periphery of a localized area by a pairof opposed punch members on opposite sides of said area which are movedtoward each other to squeeze the material in said area between them,each punch member having a hollow end with a peripheral cutting edge andan inclined peripheral surface extending inwardly from said edge andaxially outwardly to form said hollow end, the force exerting saidpressure including a centripetal component applied to said material bysaid inclined surfaces on each side of said material to force thematerial inwardly from the periphery toward the center and therebyincrease the thickness of the material in the central portion of saidlocalized area, while reducing the thickness adjacent the periphery ofthe area, forming an aperture in said localized area having acylindrical wall portion and an axial groove in said wall portion,shaving said wall of said aperture from the end of said aperture with apunch coaxial of said aperture having a continuous wall of greaterdiameter than said aperture and a helical surface on itsend intersectingsaid wall on a helical line to form a cutting edge, said cutting edgeextending completely about the periphery of the end of said punch andshaving the wall of said opening along a surface concentric to said wallportion and axially inwardly along an axially and circumferentiallyinclined line which extends to said groove to upset the metal of saidwall and form a helical rib on said cylindrical wall with one end ofsaid rib intersecting the edge of said groove to form an inwardlyextending tooth at the intersection with the wall of said groove, theheight of said rib being proportional along its length from said toothto its opposite end to its distance from the end of said aperture.

5. The method of forming fastening means as claimed in claim 1, in whicha plurality of breaks is formed in the wall of said aperture and thecutting edge of said punch shaves the wall of said aperture along acontinuous line extending between successive breaks.

1. The method of forming fastening means on an article for engagementwith a shank on relative rotation of said shank and article, comprisingforming an aperture in said article with the wall of said apertureprovided with at least one axially extending discontinuity to form abreak in said wall with a surface extending radially outwardly from saidwall, swaging the wall of said aperture radially inwardly by shaving themetal of said wall axially inwardly from the end of said aperture with apunch coaxial of said aperture having a continuous wall of greaterdiameter than said aperture and a helical surface on its endintersecting said wall on a helical line to form a cutting edge, saidpunch having a cutting edge extending completely about the periphery ofthe end of said punch and shaving the wall of said opening along asurface concentric to said wall and on a helical line intersecting thewall of said break to form a helical rib along the wall of said aperturewith one end of said rib intersecting the radially extending surface ofsaid break and forming an inwardly extending tooth at the intersection,the radial height of said rib increasing from said tooth and at anypoint being proportional to the distance of the rib from the end of theaperture.
 2. The method of forming fastening means as claimed in claim 1in which a plurality of breaks is formed in the wall of said apertureand each rib extends from one break to the next succeeding break, andsaid punch has a plurality of helical surfaces intersecting saidcontinuous wall in helical cutting edges to form a plurality of ribs onsaid wall of said aperture, said ribs being spaced equal distances fromthe end of said aperture, the end of each rib farthest from the adjacentsurface at its intersection with the break forming an inwardly heighttooth of greater radial huight than the tooth at the other end, thecorresponding end teeth of all said ribs being equal in radial height.3. The method of forming fastening means in an article for engagement bya shank on relative rotation, comprising the steps of forming anaperture through said article with concentric arcuate walls spaced bybreaks in the periphery of the aperture, moving opposed punch membersinto said aperture toward each other from opposite sides of saidarticle, each punch member having a continuous wall and helical surfaceson the end intersecting said continuous wall in helical cutting edges ofgreater external diameter than and concentric with the concentricarcuate walls of said aperture, swaging the edges of said arcuate wallsby engagement of the helical edges of each of said punch members withthe edges of said arcuate walls and with the helical edges on said punchmembers concentric to said walls to form helical ribs on said arcuatewalls, each rib extending along one wall from a break adjacent thesurface of said article radially inwardly and axially toward the nextbreak, the end of each rib nearest one surface at the intersection withthe adjacent break forming an inwardly protecting tooth to engage ashank initially when inserted from the side with said one surface, thehelical ribs formed by each punch member being spaced equal distancesfrom the end of said aperture to form ribs equal in height, the helicalribs formed by opposite punch members lying in the same helical curves,so that the high end of one rib engages in the groove cut in the shankby the low end of the opposite rib.
 4. The method of forming a femalethreaded fastener in thin, flat sheet material which comprises exertingpressure on said material at an acute angle to the surface about theperiphery of a localized area by a pair of opposed punch members onopposite sides of said area which are moved toward each other to squeezethe material in said area between them, each punch member having ahollow end with a peripheral cutting edge and an inclined peripheralsurface extending inwardly from said edge and axially outwardly to formsaid hollow end, the force exerting said pressure including acentripetal component applied to said material by said inclined surfaceson each side of said material to force the material inwardly from theperiphery toward the center and thereby increase the thickness of thematerial in the central portion of said localized area, while reducingthe thickness adjacent the periphery of the area, forming an aperture insaid localized area having a cylindrical wall portion and an axialgroove in said wall portion, shaving said wall of said aperture from theend of said aperture with a punch coaxial of said aperture having acontinuous wall of greater diameter than said aperture and a helicalsurface on its end intersecting said wall on a helical line to form acutting edge, said cutting edge extending completely about the peripheryof the end of said punch and shaving the wall of said opening along asurface concentric to said wall portion and axially inwardly along anaxially and circumferentially inclined line which extends to said grooveto upset the metal of said wall and form a helical rib on saidcylindrical wall with one end of said rib intersecting the edge of saidgroove to form an inwardly extending tooth at the intersection with thewall of said groove, the height of said rib being proportional along itslength from said tooth to its opposite end to its distance from the endof said aperture.
 5. The method of forming fastening means as claimed inclaim 1, in which a plurality of breaks is formed in the wall of saidaperture and the cutting edge of said punch shaves the wall of saidaperture along a continuous line extending between successive breaks.